Advertisement

Journal of Bionic Engineering

, Volume 5, Issue 4, pp 282–290 | Cite as

Machine Vision Based Measurement of Dynamic Contact Angles in Microchannel Flows

  • Valtteri Heiskanen
  • Kalle Marjanen
  • Pasi KallioEmail author
Article

Abstract

When characterizing flows in miniaturized channels, the determination of the dynamic contact angle is important. By measuring the dynamic contact angle, the flow properties of the flowing liquid and the effect of material properties on the flow can be characterized. A machine vision based system to measure the contact angle of front or rear menisci of a moving liquid plug is described in this article. In this research, transparent flow channels fabricated on thermoplastic polymer and sealed with an adhesive tape are used. The transparency of the channels enables image based monitoring and measurement of flow variables, including the dynamic contact angle. It is shown that the dynamic angle can be measured from a liquid flow in a channel using the image based measurement system. An image processing algorithm has been developed in a MATLAB® environment. Images are taken using a CCD camera and the channels are illuminated using a custom made ring light. Two fitting methods, a circle and two parabolas, are experimented and the results are compared in the measurement of the dynamic contact angles.

Keywords

digital image processing machine vision microfluidics microchannel flow dynamic contact angle image based measurement 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. [1]
    Nguyen N-T, Wereley S. Fundamentals and Applications of Microfluidics, 1st ed., Artech House, Boston, 2002.zbMATHGoogle Scholar
  2. [2]
    Li L, Kang K, Ye D. A contact angle measurement method for the droplets in EWOD-based chips. Proceeding of the 2nd IEEE International Conference on Nano/Micro Engineered and Molecular Systems, Bangkok, Thailand, 2007, 1071–1075.Google Scholar
  3. [3]
    Sankowski D, Strzecha K, Jezewski S, Senkara J, Lobodzinski W. Computerized device with CCD camera for measurement of surface tension and wetting angle in solid-liquid systems. Proceedings of the 16th IEEE Instrumentation and Measurement Technology Conference, 1999, 1, 164–168.Google Scholar
  4. [4]
    Mohammadi R, Finlay W H, Roa W, Amirfazli A. Determination of contact angle of microspheres by microscopy methods. Proceedings of the International Conference on MEMS, NANO and Smart Systems, 2003, 84–88.Google Scholar
  5. [5]
    Zhang J, Kwok D Y. Lattice Boltzmann simulations of bubble dynamics in microchannels. Proceedings of the International Conference on MEMS, NANO and Smart Systems, 2004, 78–83.Google Scholar
  6. [6]
    Homma H, Lee C-R, Kuroyagi T, Izumi K. Evaluation of time variation of hydrophobicity of silicone rubber using dynamic contact angle measurement. Proceedings of the 6th International Conference on Properties and Applications of Dielectric Materials, 2000, 2, 637–640.Google Scholar
  7. [7]
    Cho H, Kim H-Y, Kang J Y, Kim T S. How the capillary burst microvalve works. Journal of Colloid and Interface Science, 2007, 306, 379–385.CrossRefGoogle Scholar
  8. [8]
    Shui L, Eijkel J C T, Van Den Berg A. Multiphase flow in micro- and nanochannels. Sensors and Actuators B, 2007, 121, 263–276.CrossRefGoogle Scholar
  9. [9]
    Adhesives Research, [2008-01-25], http://www.adhesivesresearch.com/
  10. [10]
    Gonzales R C, Woods R E. Digital Image Processing, 3rd ed., Prentice Hall, New Jersey, 2007.Google Scholar
  11. [11]
    Heiskanen V, Kallio P, Marjanen K. Machine vision based measurement of dynamic contact angle in microchannel flows. Proceedings of 6th Int. ASME Conf. on Nanochannels, Microchannels and Minichannels (ICNMM2008), Darmstadt, Germany, 2008, ICNMM2008-62063.Google Scholar

Copyright information

© Jilin University 2008

Authors and Affiliations

  • Valtteri Heiskanen
    • 1
  • Kalle Marjanen
    • 2
  • Pasi Kallio
    • 1
    Email author
  1. 1.Micro- and Nanosystems Research Group, Department of Automation Science and EngineeringTampere University of TechnologyTampereFinland
  2. 2.Measurements Based on Images Research Group, Department of Automation Science and EngineeringTampere University of TechnologyTampereFinland

Personalised recommendations